/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2020.06.11 19:22:14
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;



template< typename T >
struct BinaryIndexedTree {
    std::vector< T > data;
    BinaryIndexedTree(int sz) {
        data.assign(++sz, 0);
    }
    
    inline T sum(int k) {
        T ret = 0;
        for (++k; k > 0; k -= k & -k) ret += data[k];
        return (ret);
    }
    
    inline T sum(int left, int right) {
        return sum(right) - sum(left - 1);
    }
    
    
    inline void add(int k, T x) {
        for (++k; k < data.size(); k += k & -k) data[k] += x;
    }
    
    
    
    int get(ll k) {
        ++k;
        int res = 0;
        int N = 1; while (N < (int)data.size()) N *= 2;
        for (int i = N / 2; i > 0; i /= 2) {
            if (res + i < (int)data.size() && data[res + i] < k) {
                k = k - data[res + i];
                res = res + i;
            }
        }
        return res + 1;
    }
    void print() {
        std::cout << "[ ";
        for (int i = 0; i < data.size() - 1; i++) {
            std::cout << sum(i, i);
            if (i < data.size() - 2) cout << ", ";
        }
        std::cout << " ]" << endl;
    }
};
int main() {
    int n;cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    BinaryIndexedTree<int> bit(n);
    set<pair<int,int>> st; 
    ll ans = 0;
    for (int i = 0; i < n; i++) {
        int l,r;cin >> l >> r;
        while(!st.empty() && (*st.begin()).first < a[i]) {
            bit.add((*st.begin()).second,-1);
            st.erase(st.begin());
        }
        auto p = lower_bound(a.begin(), a.end(), a[i]-l);
        if (p != a.end()) ans += bit.sum(p-a.begin(),n-1);
        st.insert({a[i]+r,i});
        bit.add(i,1);
    }
    cout << ans << endl;
    return 0;
}